2008-04-17	348.1	16.99		20.49	"Average speed over this tank was 32.6 m.p.h., reflecting more city and traffic driving. This mileage is below my 3, 5, and 10 tank moving averages."
2008-04-22	289.6	14.46		20.03	"Not sure why this was so low, it's below my regression line for tank mileage as a function of average speed over the tank full. It was also 1.5 m.p.g. under the indication in the instrument panel display. The display nearly always reads high, but typically about 06. to 0.7 m.p.g. difference. My 3, 5, and 10 tank moving averages are currently: 20.58; 20.84; and 20.76."
2008-04-28	326	14.52		22.45	"Average speed this tank full was 4.81 m.p.h. higher than the ""average of the averages"" (40.6 m.p.h. vs. 35.79 m.p.h.). Presumably this means less local driving and fewer traffic jams, thus resulting in a higher than typical fuel economy for this tank."
2008-05-02	315.7	14.87		21.23	"Fairly standard tank full, relatively little city and traffic driving as indicated by the average speed over the tank full of 38.20 m.p.h., compared to the average average speed (no typo there) of 35.87 m.p.h."
2008-05-08	305.9	14.63		20.91	"My average speed over this tank full was 34.1, my regression line of tank mileage as a function of speed predicted 20.17. When I saw that the tank mileage was going to be poor due to some local driving I had to do on the first day of this tank full, I reduced my freeway speed from 55 m.p.h. to 53 m.p.h. I assume this is why I did better than the prediction based on speed, but I don't know if I can keep the speed that low."
2008-05-15	320.9	14.37		22.33	"Average speed for this tank full was 39.0 m.p.h. vs. ""median average"" speed of 35.9 m.p.h. This could be lack of traffic jams, more freeway trips, etc. This woiuld explain the relatively high tank mileage in comparison to the the three, five, and ten tank moving averages of 21.5 m.p.g., 21.4 m.p.g., and 21.3 m.p.g. respectively."
2008-05-21	318	14.76		21.54	"Did surprisingly well considering my average speed (my surrogate for the effects of local driving and traffic james) for this tank. My regression line predicts, for the average speed of 34.5, that my gas mileage would be 20.3 m.p.g. rather than the 21.5 I got. I'm not sure what I did right - could be an artifact of inconsistent fill levels (too high on the subject tank full or too low on the current tank)."
2008-05-27	307.9	16.52		18.64	"Terrible tank full. I did more surface street ""running around"" than typical, but my average tank mileage indication, which typically shows somewhere around 0.6 - 0.7 m.p.g. higher than the actual miles divided by gallons calculation at fill up showed 21.1 when the calculation yielded 18.63. I have no explanation other then somehow filling up way way high into the neck of the tank. I always ""top off"" and have a feel for when the last few drops go in. Today, when I got to that point, all of the sudden the pump ran for another gallon and a half or so. We'll see what happens next time. At $4.239 for premium, I hope it's a while. On the other hand, with fuel going up about 5 cents per gallon every time I fill up, maybe I should fill up daily."
2008-05-31	318.5	13.14		24.24	"Dramatically better gas mileage with not a large change in average speed. Somehow, I must have been able to overfill the tank by a healthy 1.5 gallons. I can't figure out how though."
2008-06-04	283.8	13.41		21.16	"Fairly standard, typical tank full, other than paying $4.599 per gallon, 22 cents more than on Saturday. Wow. Average speed was 35.1 m.p.h., which is also typical. No surprises."
2008-06-10	325.3	15.31		21.25	"Not much to say on this one. The data point of tank miles per gallon plotted as a function of average speed over the tank full (as displayed on the LR3's panel) fell quite close to the regression line."
2008-06-14	293.5	14.16		20.73	"This was another tank I thought would be very good. The average as shown on the display was 22.3. It's typical that the calculated mileage at fill up is about 0.6 or 0.7 miles per gallon less than the display, but 1.6 is much higher than usual. Further, average speed was fairly high at 37.2 m.p.h. I guess I must have filled way up into the neck again. This is why I keep the 3, 5, and 10 tank moving averages which currently stand at 21.04 m.p.g., 21.2 m.p.g., and 21.44 m.p.g. respectively. Moving averages smooth out erratic data and emphasize trends."
2008-06-17	311.4	14		22.24	"Mileage was above both the expected value from the mileage as a function of average speed regression and above the indicated average mileage (which is quite unusual). These indicate that it's very likely the previousl fill up was well above the normal level in the tank/neck."
2008-06-20	337.8	14.46		23.36	"Average speed over this tan full was very high, most of the driving was unimpeded freeway on a business trip to Santa Barbara. Even so, the mileage was above the regression line of m.p.g. as a function of speed over a tank full. That line would have predicted 22.3 m.p.g. rather than the 23.4 actually recorded. I'm also back to the typical calculated m.p.g. being below the indicated average on the display - this time, by 1 m.p.g."
2008-06-27	334.6	15.79		21.19	"Replaced the front discs on the vehicle and was afraid that I'd have deteriorated mileage until they ""wore in"" as happened on my previous vehicle. It looks as if that didn't happen. The ""mileage as a function of tank average speed"" point plotted precisely on the regression line - 37.8 m.p.h.,21.19 m.p.g."
2008-07-03	346.3	15.95		21.71	"I seem to be safe from the effects of replacement of my front disk pads, a service item that ruined my gas mileage for weeks on my previous vehicle. The ""mileage as a function of average speed over tank full"" point was above the regression line. For those with a statistical bent, the coefficient of determination is 0.437, the correlation coefficient is 0.661 for a linear function. The actual regression line is y=0.2353*x+12.295 where y is predicted m.p.g., x is average speed in miles per hour over a tank full. Clearly, this measures encounters with traffic, highway vs. city driving, etc. and is not a prediction that the faster I go, the better mileage I can achieve. Typical average speeds are in the 37 m.p.h. range, the lowest has been 27 m.p.h., the highest was 43.6 m.p.h."
2008-07-12	324.1	15.37	$4.719	21.09	"I had to do a lot of local errands for some home upkeep projects. That means down and up the hill to my house. A very inefficient tank full. Average speed was 33.8 and the 21.08 m.p.g. was actually above that predicted by the regression line."
2008-07-20	299.6	14.49	$4.639	20.68	"Another low mileage tank full. My three tank moving average is now barely above 21 m.p.g, much to my chagrin. It's been as high as 22.26 m.p.g. The calculated m.p.g. was still slightly above that predicted by the average speed over the tank full (33.8 m.p.h.)."
2008-07-24	297.4	14.08	$4.559	21.12	"My three tank moving average is now below 21.m.p.g. This is quite disappointing, however, this fill up has been similar to my last few in that the mileage predicted by the regression line of miles per gallon for a tank full as a function of average speed over that tank full is less than what I actually achieved. I think I'll start tracking predicted versus achieved mileage. This should be a better indication of my hypermiling technique than just raw mile per gallon."
2008-07-31	329	14.96	$4.439	21.99	"Again, a little above the speed predicted by my average speed over the tank full. I've added a calculation and graph of fuel cost per mile to my spreadsheet. This tank full continues the downward trend caused by gasoline prices (which I've tracked since beginning this logging in 2005) continuing down. Bet it doesn't get to where it was when I started."
2008-08-06	367.3	17.02	$4.359	21.58	"Pretty mundane tank full, another instance of achieving above the prediction by average speed. Of course, over time that will adjust since it's a least squares regression line of all data."
2008-08-13	388.8	17.86	$4.239	21.77	"Still slightly above the regression line relating gas mileage to average speed over the tank. That speed was 38.7 m.p.h., the predicted mileage is 21.47, the actual was 21.77."
2008-08-21	354.8	16.54	$4.139	21.45	"Mundane. One of my higher ""average speed"" tanks at 40.1 m.p.h. and very slightly below the prediction for that speed. I need to start doing some ""unobtrusive"" ecomods because I've come pretty close (I think) to what can be done in my vehicle with driving technique. The only thing I can think of in that vein is to be more aggressive in stop light engine shut offs. But, though everything I've been able to find and read indicates something like 10 seconds as the turn off/restart vs. idle break even point, that doesn't feel right, so I guess experimentation there is in order."
2008-08-27	311.1	14.14	$4.099	22	"Not much to say about this tank full. Above the m.p.g.=f(m.p.h.) curve. The coefficient of determination is increasing in this curve, now at .4358."
2008-09-03	364.8	17.01	$4.039	21.45	"Slightly above regression line for average speed."
2008-09-09	328	14.79	$3.979	22.18	"My regression line for mileage achieved as a function of average speed over the tank full is getting tighter. This was 39.9 m.p.h. average speed for a mileage of 22.18."
2008-09-15	332.8	15.66	$3.939	21.25	"It's always surprising to me that what happens at the start of a tank seems to set the scene for the entire tank - if it starts of poorly (local commutes at low speed, traffic jams, etc.) it's seemingly almost impossible to recover. This, obviously, was one such tank."
2008-09-22	350.4	16.58	$3.839	21.13	"It looks like I'm not going to be able to exceed about 21.6 for a long term average mileage without vehicle modifications. It also looks like R^2, the coefficient of determination for my ""mileage over tank full as a function of average speed over tank full"" will not get much past 0.42. I guess it's time for aero mods."
2008-09-25	367.7	16.05	$3.839	22.91	"Most of this tank was freeway driving. Average speed was over 45 m.p.h., the highest average I've recoreded to date. It did, however, fall precisely on the regression line."
2008-10-01	329.5	15.18	$3.799	21.71	"Not much to be said. This tank is right at the nexus of the three tank, five tank, and 10 tank moving averages."
2008-10-08	380.6	17.88	$3.679	21.29	"Very disappointing. The tank average indicated in the vehicle display was 22.3, the calculation revealed 21.3. It's usually lower than the indication but not by a full m.p.g."
2008-10-16	387	18.3	$3.579	21.15	"Ugh. Bad news. 21.15 m.p.g. brings all my averages down. My first 40 miles or so were in jammed traffic, and it seems like starting off badly in a tankful is not recoverable."
2008-10-21	358.3	17.12	$3.479	20.93	"Worse and worse. I seem to keep getting caught in massive traffic jams, and the mileage, for reasons unknown to me, is extremely sensitive to the early part of a tank full. I'm now below 21.5 m.p.g. on my most accurate average mileage indication, at 21.44 m.p.g."
2008-10-28	363.7	17.07	$3.219	21.31	"For unknown reasons, my trend is clearly downward in average mileage. The 3, 5, and 10 tank full moving averages clearly indicate this. I don't know why, the car isn't in need of a tune up. Could it be changes in the fuel formulation? I nearly always refill at the same station, most of the time at the same pump. I guess I can check tire pressure (again), etc. but I'm not pleased."
2008-11-04	327	15.96	$2.939	20.49	"Worse and worse. I don't know what's up."
2008-11-08	313.5	14	$2.839	22.39	"Back above the regression for mileage as function of average speed, but still not where I'd like to be."
2008-11-14	361.7	17.51	$2.679	20.66	"20.66 m.p.g. is NOT making me happy. I seem to be on a bad trend. Winter blend issues? I wouldn't think so."
2008-11-20	352	16.69	$2.459	21.09	"Nothing in particular to comment on about this, other than the fact that the regression line is becoming more and more accurate."
2008-11-26	352.3	17.91	$2.239	19.67	"I spent almost this entire tank full on local trips for a variety of semi-emergency reasons, thus the low number. Nevertheless, it fell right on the regression line (actually slightly above) of miles per gallon as a function of average speed."
2008-12-03	345	17.44	$2.139	19.78	"All I can say is "
2008-12-08	311.5	15.2	$2.039	20.49	"I sure don't know what I'm doing wrong, but something is amiss. All my indicators are down. My three tank moving average is under 20 m.p.g., a level not seen since March. I don't get it."
2008-12-11	330.5	15.9	$1.979	20.79	"The misery continues."
2008-12-17	362.9	19.14	$1.939	18.96	"Winter blend? Rain? Traffic? Temperature? It's all bad."
2008-12-24	361.4	18.4	$2.019	19.64	"My frustration level with my inability to achieve decent mileage (as I have before) is reaching a maximum. At least a gallon of gasoline is, for the moment, relatively cheap."
2008-12-31	433.5	20.03	$2.059	21.64	""
2009-01-08	356.4	17.94	$2.199	19.87	""
2009-01-14	314.4	16.93	$2.239	18.57	""
2009-01-19	337.8	14.77	$2.299	22.87	"Every so often I have a sequence of two fill ups where, for whatever reason, the tank holds way more than normal and I show a very low mileage, followed by a fill up where it reverts to normal and I show a very high mileage. These last two are such a sequence. I fill up at the same station and almost always the same pump, but the ""large"" fill was at a different pump, so perhaps that explains it."
2009-01-24	382.5	18.04	$2.339	21.2	"It's looking like the major problem was wheel alignment. I had new tires put on and an alignment, fuel economy is improving noticeably."
2009-01-30	320.6	15.01	$2.279	21.36	"The recovery continues, to a certain extent."
2009-02-06	371.6	18.22	$2.399	20.4	""
2009-02-13	367.9	17.99	$2.499	20.45	""
2009-03-04	319.4	17.1	$2.439	18.68	""
2009-03-06	296.1	14.13	$2.399	20.96	""
2009-03-11	302.3	14.51	$2.399	20.83	""
2009-03-16	385	18.44	$2.399	20.88	""
2009-03-23	337.9	16.1	$2.339	20.99	""
2009-03-27	322.4	15.05	$2.439	21.42	""
2009-04-02	442.9	20.97	$2.499	21.12	""
2009-04-09	321.5	15.63	$2.579	20.57	""
2009-04-15	405.5	20.17	$253.9	20.1	""
2009-04-22	366.1	17.95	$2.579	20.4	""
2009-04-29	384.4	18.26	$2.539	21.05	""
2009-05-12	359.4	17.36	$2.699	20.7	""
2009-05-19	353.6	17.45	$2.839	20.26	""
2009-05-28	355.7	17.13	$2.899	20.76	""
2009-06-05	397.2	18.41	$3.139	21.58	""
2009-06-14	433.1	20.79	$3.239	20.83	""
2009-07-02	327.4	14.08	$3.199	23.25	""
2009-07-08	334.6	15.72	$3.139	21.28	""
2009-07-15	374.5	17.67	$3.099	21.19	""
2009-07-22	384.3	17.72	$3.039	21.69	""
2009-07-23	314.9	15.93	$3.199	19.77	""
2009-07-27	382.8	18.61	$3.039	20.57	""
2009-08-04	394.2	18.17	$3.239	21.7	""
2009-08-10	421.6	21.35	$3.299	19.75	""
2009-08-19	426.1	20.28	$3.239	21.01	""
2009-08-25	491.8	21.6	$3.239	22.77	""
2009-09-02	406.8	20.58	$3.239	19.77	"The wild fluctuations in the last few tanks are attributed to using different pumps at the same station. The cutoff makes a huge difference. Sometimes (like today) there's a car at the pump I usually use, my second choice adds a healthy gallon more before cutting off. In the long run, of course, these measurement errors even out."